Unwanted rear sag - Towing Teardrop with 4th Gen 4Runner

[chbolling]

I have a 4th Gen 4Runner with a 3" OME Lift, rock sliders, some armor, a drawer system, RIG'd spare tire swing, and a Tepui Kukenam rooftop tent and a rod vault (point is, I carry some gear on/in my truck). The rear springs are the OME 896 (supposed to accommodate an additional 330 lbs).

I tow a SoCal teardrops 510xs (let's call the tongue dry weight 140+ pounds)

When towing, there are more than a few inches of sag, and I'd love to have it level. Is this a spring issue (i.e. do a need a heavier rear spring)? How can I resolve this? The rig does ok in travel. I don't notice any really unusual driving characteristics other than what is a bit less planted front end - it's not particularly skittish.

Thoughts or suggestions? (the pic attached is with the jack stands in place, but is an approximation of the sag)

 

[4000lbsOfGoat]

Is this a spring issue (i.e. do a need a heavier rear spring)?

Yes. While a heavier rear spring might make the ride a bit firm when you aren't towing the trailer, it is really the best solution (IMHO).

I pulled my teardrop for around 10k miles with Icon RXT springs on my Tacoma (in about 8 months). They are supposed to be "heavy duty" springs as well but the sag got pretty bad. I ended up replacing those springs with Deaver Expedition Stage 3's, which are about the heaviest spring you can put on a Tacoma. I've pulled the trailer over 5000 miles with those springs and they have not sagged at all. I'll actually need to get a lower ball mount to get the trailer to sit level again...

I know that you're looking at a different animal with the coil springs on the 4 Runner but I've seen seriously heavily loaded T4Rs that still sat proud in the rear so I know that there are heavy enough springs out there.

Cheers!

 

[Herbie]

I mean, doing the math on your load will probably be enlightening. Stated tongue weight + Rig'd alone is ~200lbs. You didn't say who made your drawer system, but based on a quick googling, I'd wager that Tongue Weight + Rig'd swing + drawer system eats up ALL of that 330lbs the heavier springs would have bought you. Plus at least 2/3 of that weight is RIGHT on the ass-end, where it has the longest lever to work against the springs.

Add in the RTT, sliders, armor, and miscellaneous gear, and you're likely just overloading those springs on the rear.

 

[mep1811]

Heavier rear springs are in order. You can try airbags but new springs would be better.

 

[Porkchopexpress]

140 lbs on the tongue is pretty minimal. I think your overland kit on the truck is heavy to start with so the trailer just pushes you over the top. I agree with the posts above that firmer rear springs are probably required, (or maybe they are just worn out?). I would also check your weight on a truck stop scale without the trailer just to see where you are.

 

[PV Hiker]

Some years back I towed a 17' Casita travel trailer with my 2005 4-Runner. So I called National Springs to make custom coils on all 4 corners. The rears I had made them progressive 450 pound loading. Comfortable ride not towing and towing. Don't own the trailer anymore and the ride is enjoyable. I go to the garden shop and load up 500 pounds of fertilizer in the back and still seems to look level enough.

So either add air bags for a level ride towing or new rear coils designed for tongue weight towing.

To have custom ones made you will need the weights front and rear, especially need to actually weight that trailer at the tongue as that box loaded up adds more. The rear tire hanging off the back cantilever weight more also.

 

[(none)]

I have some 5th gen dobbinson overland springs if ya want to go that route. I believe they will work in a 4th gen.
I put airbags in my icon coils in the 5th gen I had. I never liked the way they rode, to level up the back it rode very stiff. I now have airbags in the back of my frontier (with leaf springs) and the airbags do not deteriorate the ride nearly as much.

 

[Louisd75]

I have a 4th Gen 4Runner with a 3" OME Lift, rock sliders, some armor, a drawer system, RIG'd spare tire swing, and a Tepui Kukenam rooftop tent and a rod vault (point is, I carry some gear on/in my truck). The rear springs are the OME 896 (supposed to accommodate an additional 330 lbs).

I tow a SoCal teardrops 510xs (let's call the tongue dry weight 140+ pounds)

When towing, there are more than a few inches of sag, and I'd love to have it level. Is this a spring issue (i.e. do a need a heavier rear spring)? How can I resolve this? The rig does ok in travel. I don't notice any really unusual driving characteristics other than what is a bit less planted front end - it's not particularly skittish.

Thoughts or suggestions? (the pic attached is with the jack stands in place, but is an approximation of the sag)View attachment 746853

Have you measured the actual tongue weight or is that a seat of the pants measure? Only reason I ask is that SoCal lists the dry tongue weight for your model at between 190 and 225 lbs depending on which page of the website you're looking at. It would probably be best if you could load the trailer up and measure the tongue weight, then get the rear axle weight of the 4runner to get the best idea of what your actual load is. It'll make it easier to come up with a good solution, otherwise you're kind of guessing

 

[chbolling]

Have you measured the actual tongue weight or is that a seat of the pants measure? Only reason I ask is that SoCal lists the dry tongue weight for your model at between 190 and 225 lbs depending on which page of the website you're looking at. It would probably be best if you could load the trailer up and measure the tongue weight, then get the rear axle weight of the 4runner to get the best idea of what your actual load is. It'll make it easier to come up with a good solution, otherwise you're kind of guessing

I went to the site and saw what was listed for the Borego, so it was an innacurate swag. I need to think through how to get accurate tongue and axle weight, but that seems like an easy google. Thanks for the input - committed to getting this rig dialed

 

[Louisd75]

I went to the site and saw what was listed for the Borego, so it was an innacurate swag. I need to think through how to get accurate tongue and axle weight, but that seems like an easy google. Thanks for the input - committed to getting this rig dialed

Depending on how you load up the tongue storage can have a huge impact on your tongue weight. I wound up buying a tongue weight scale to play around with loading. Prior to that I would use a small weigh station that's relatively close to home. It's the style that weighs each axle as you drive slowly over it. I'd drive over and jot down each axle weight with the trailer, then disconnect the trailer and do it over again to get the tow vehicle axle weights. The change in rear axle weight gives you a decently close tongue weight. It's not perfect, you'd need to do some math and factor in the difference in front axle weight as well if you wanted it to be exact. The weigh station is open to the public, it's just a small one along the side of a local highway. I've never seen it actually in service but the scale is usually on. I wouldn't try it at one of the busy scales that the commercial drivers are using.

There are ways of measuring using a bathroom scale and setting up a lever system to get an accurate measurement. My driveway and garage aren't really conducive to that method so I wound up getting a Sherline one off of Amazon on sale.

 

[billiebob]

lots of solutions once you change springs bur FIRESTONE AIR BAGS might be the fast, simple, cheap, adjustable solution.

 

[javajoe79]

If you like the ride and behavior without the trailer and gear then airbags would be the best solution. Easy install and it will give you the ability to change the pressure based on what you're hauling.

 

[Betarocker]

Installing the bags inside the coils is a pain. Did it for my brother's 4runner a few years ago, but this summer we removed them and the coils, and replaced with stiffer coils. One bag was leaking, and he keeps all his gear in a heavy plywood storage system all the time. He's happy with the outcome. Don't remember the coil brand he went with currently, but the ones we removed are OME 2" lift